Speed is how fast something moves or happens. When a car travels at high speed, it covers a lot of distance quickly. When you finish your homework with speed, you complete it rapidly.

Speed measures the rate of movement: miles per hour, feet per second, or even pages per minute when you're reading. A cheetah has incredible speed, reaching 70 miles per hour in short bursts. A rocket needs tremendous speed to escape Earth's gravity.

The word also describes quickness in general. You might solve a puzzle with impressive speed, or a hockey player might have great speed on the ice. In manufacturing, an assembly line's speed determines how many products get made each hour.

When people talk about “picking up speed,” they mean going faster and faster, like a bicycle rolling downhill. “At full speed” means as fast as possible. As a verb, speed up means to go faster, and slow down means the opposite.

There's a difference between speed and velocity in physics: velocity includes direction, while speed is just how fast you're going. But in everyday conversation, people use speed for both ideas.

Notice that speed isn't always better. A sprinter needs speed to win a race, but a surgeon needs careful, steady hands. Sometimes moving too fast causes mistakes. The trick is matching your speed to the task at hand.